How Do Carnivorous Plants Catch Insects?

Different carnivorous plants use different mechanisms to catch their prey. How does it all work?

Carnivorous plants have long fascinated me. I wondered how they catch or digest their meal. I was shocked to learn that not all of them catch insects by snapping at them like Venus flytraps do.

So how exactly do they catch insects?

Methods They Use to Trap Food

Attracting a meal is the first step. Carnivorous plants use colors, nectars, and fragrances to attract their prey, and some plants even glow in the dark.

Once an insect has been attracted to the plant by the possible food, the plant sets its trap. To do this, plants use a couple different strategies.

Snap Traps

Snap traps resemble open mouths with sensitive hairs on the inside that, when rubbed, cause the jaw to close. Leaves open and close around unsuspecting prey.

Common plants that fall into this category include Venus flytraps and waterwheels. 

A common housefly being eaten by a carnivorous houseplant

Pitfall Traps

The pitfall trap is the simplest trapping mechanism employed by carnivorous plants. This trap is a basic bucket-like container that contains digesting fluid and into. Prey either falls or slips into it.

Pitcher plants, in particular, use this method to trap their prey. 

Pitfall traps plant, bucket type leaf

Flypaper Traps

The sticky mucus used in flypaper traps prevents animals from being able to fly or walk away after they land on the plants’ leaves. Insects become trapped on the leaf’s face, which folds in to keep them from escaping.

Sundews and butterworts employ this strategy.

An insect caught in a flypaper trap plant

Bladder Traps

Bladderworts catch their food by waiting for their prey (often tiny crustaceans) to touch trigger hairs on the trapdoor, which then seals the trap. It has a bladder that snaps open when this happens.

Mosquitos caught in the bladder traps of plants

Enzymes for Digestion

After capturing its prey, a carnivorous plant takes several days to digest it. Unlike humans or animals, carnivorous plants do not chew their food. Instead, they use enzymes to break it down. Some plants, such as pitcher plants, use microbes instead of enzymes, which lets them absorb even more nutrients.

Why Do They Eat Insects?

Most plants receive nutrients from the soil through their roots. But carnivorous plants originated in nutrient-deficient settings, such as bogs and marshes. In order to thrive, they had to come up with a different source for nutrients.

With few other plants as competition, carnivorous plants mutated to obtain the nutrients they require by devouring insects.

Where Do They Typically Grow?

Carnivorous plants vary in form and size, but they all have certain basic characteristics, such as a preference for hot, humid, and moist conditions. This makes them ideal for living in rainforests across the world, particularly in South America and Asia. 

However, there are carnivorous plants that live in more moderate climates, such as the Venus flytrap, which may be found in both North and South Carolina.

Alaine Connolly
Alaine has been working way too hard in horticulture since 1992, beautifying golf courses, resorts, and hotels. She is a part time landscape designer who works full time caring for a 28,000 square foot public garden. At home, she maintains her own 400 square feet plot. Alaine lives in northern Illinois - zone 5b.
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